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Histomorphometry in Peripheral Nerve Regeneration: Comparison of Different Axon Counting Methods. J Surg Res 2021; 268:354-362. [PMID: 34403855 DOI: 10.1016/j.jss.2021.06.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 04/16/2021] [Accepted: 06/08/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND Histomorphometry quantitatively evaluates nerve regeneration. Total myelinated fiber count (TMFC) is most accurately obtained manually across full nerve cross-sections, but most researchers opt for automated, sampled analysis. Few of the numerous techniques available have been validated. The goal of this study was to compare common histomorphometric methods (full manual [FM], sampled manual [SM], and sampled automatic [SA]) to determine their reliability and consistency. MATERIAL AND METHODS Twenty-four rats underwent sciatic nerve (SN) repair with 20mm isografts; SNs distal to the graft were analyzed. TMFC was manually determined in each full cross-section. Counts were also extrapolated from sampled fields, both manually and automatically with ImageJ software. Myelinated fiber diameter, axon diameter, and myelin sheath thickness were measured manually in full and sampled fields; G-ratio was calculated. Repeated-measures MANOVA, Spearman correlation, and Wilcoxon signed-rank tests were performed. A systematic review of histomorphometry in rat SN repair was performed to analyze the variability of techniques in the literature. RESULTS FM TMFC was 13,506 ± 4,217. Both sampled methods yielded significantly different TMFCs (SM:14.4 ± 13.4%, P< 0.001; SA:21.8 ± 44.7%, P = 0.037). All three methods strongly correlated with each other, especially FM and SM (rs = 0.912, P< 0.001). FM fiber diameter, axon diameter, and myelin sheath thickness did not differ from SM (P = 0.493, 0.209, and 0.331, respectively). 65% of papers used sampling; 78% utilized automated or semi-automated analysis. Software, sampling, and histomorphometric parameters varied widely. CONCLUSION SM and SA analysis are reliable with standardized, systematic sampling. Transparency is essential to allow comparison of data; meanwhile, researchers must be cognizant of the wide variety of methodologies in the literature.
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Bruna J, Alberti P, Calls-Cobos A, Caillaud M, Damaj MI, Navarro X. Methods for in vivo studies in rodents of chemotherapy induced peripheral neuropathy. Exp Neurol 2020; 325:113154. [PMID: 31837318 PMCID: PMC7105293 DOI: 10.1016/j.expneurol.2019.113154] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/07/2019] [Accepted: 12/10/2019] [Indexed: 12/15/2022]
Abstract
Peripheral neuropathy is one of the most common, dose limiting, and long-lasting disabling adverse events of chemotherapy treatment. Unfortunately, no treatment has proven efficacy to prevent this adverse effect in patients or improve the nerve regeneration, once it is established. Experimental models, particularly using rats and mice, are useful to investigate the mechanisms related to axonal or neuronal degeneration and target loss of function induced by neurotoxic drugs, as well as to test new strategies to prevent the development of neuropathy and to improve functional restitution. Therefore, objective and reliable methods should be applied for the assessment of function and innervation in adequately designed in vivo studies of CIPN, taking into account the impact of age, sex and species/strains features. This review gives an overview of the most useful methods to assess sensory, motor and autonomic functions, electrophysiological and morphological tests in rodent models of peripheral neuropathy, focused on CIPN. We include as well a proposal of protocols that may improve the quality and comparability of studies undertaken in different laboratories. It is recommended to apply more than one functional method for each type of function, and to perform parallel morphological studies in the same targets and models.
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Affiliation(s)
- Jordi Bruna
- Unit of Neuro-Oncology, Hospital Universitari de Bellvitge, Institut Català d'Oncologia L'Hospitalet, IDIBELL, Hospitalet de Llobregat, Barcelona, Spain; Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Paola Alberti
- Experimental Neurology Unit, School of Medicine and Surgery, University Milano Bicocca, Monza, Italy; NeuroMI (Milan Center for Neuroscience), Milan, Italy
| | - Aina Calls-Cobos
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Martial Caillaud
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
| | - Xavier Navarro
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain.
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Engelmann S, Ruewe M, Geis S, Taeger CD, Kehrer M, Tamm ER, Bleys RLAW, Zeman F, Prantl L, Kehrer A. Rapid and Precise Semi-Automatic Axon Quantification in Human Peripheral Nerves. Sci Rep 2020; 10:1935. [PMID: 32029860 PMCID: PMC7005293 DOI: 10.1038/s41598-020-58917-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 01/20/2020] [Indexed: 11/09/2022] Open
Abstract
We developed a time-efficient semi-automated axon quantification method using freeware in human cranial nerve sections stained with paraphenylenediamine (PPD). It was used to analyze a total of 1238 facial and masseteric nerve biopsies. The technique was validated by comparing manual and semi-automated quantification of 129 (10.4%) randomly selected biopsies. The software-based method demonstrated a sensitivity of 94% and a specificity of 87%. Semi-automatic axon counting was significantly faster (p < 0.001) than manual counting. It took 1 hour and 47 minutes for all 129 biopsies (averaging 50 sec per biopsy, 0.04 seconds per axon). The counting process is automatic and does not need to be supervised. Manual counting took 21 hours and 6 minutes in total (average 9 minutes and 49 seconds per biopsy, 0.52 seconds per axon). Our method showed a linear correlation to the manual counts (R = 0.944 Spearman rho). Attempts have been made by several research groups to automate axonal load quantification. These methods often require specific hard- and software and are therefore only accessible to a few specialized laboratories. Our semi-automated axon quantification is precise, reliable and time-sparing using publicly available software and should be useful for an effective axon quantification in various human peripheral nerves.
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Affiliation(s)
- S Engelmann
- Department of Plastic, Hand and Reconstructive Surgery, University Hospital Regensburg, Regensburg, Germany
| | - M Ruewe
- Department of Plastic, Hand and Reconstructive Surgery, University Hospital Regensburg, Regensburg, Germany
| | - S Geis
- Department of Plastic, Hand and Reconstructive Surgery, University Hospital Regensburg, Regensburg, Germany
| | - C D Taeger
- Department of Plastic, Hand and Reconstructive Surgery, University Hospital Regensburg, Regensburg, Germany
| | - M Kehrer
- Department of Trauma Surgery, University Hospital Bonn, Bonn, Germany
| | - E R Tamm
- Institute of Human Anatomy, University of Regensburg, Regensburg, Germany
| | - R L A W Bleys
- Department of Anatomy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - F Zeman
- Center for Clinical Studies, University Hospital Regensburg, Regensburg, Germany
| | - L Prantl
- Department of Plastic, Hand and Reconstructive Surgery, University Hospital Regensburg, Regensburg, Germany
| | - A Kehrer
- Department of Plastic, Hand and Reconstructive Surgery, University Hospital Regensburg, Regensburg, Germany.
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Fernandes A, Coelho T, Rodrigues A, Felgueiras H, Oliveira P, Guimarães A, Melo-Pires M, Taipa R. Clinicopathological correlations of sural nerve biopsies in TTR Val30Met familial amyloid polyneuropathy. Brain Commun 2019; 1:fcz032. [PMID: 32954271 PMCID: PMC7425381 DOI: 10.1093/braincomms/fcz032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/18/2019] [Accepted: 10/07/2019] [Indexed: 01/02/2023] Open
Abstract
Familial amyloid polyneuropathy with the substitution of methionine for valine at position 30 in the TTR gene is the most common type of hereditary transthyretin amyloidosis. Although several authors have previously reported a size-dependent fibre loss, predominantly involving unmyelinated and small-diameter myelinated fibres, the mechanisms of nerve fibre loss have not been fully understood. In this study, we establish the morphometric pattern of peripheral neuropathy in patients with familial amyloid polyneuropathy and asymptomatic mutation carriers in the biopsies from our archive and correlated the pathological findings with clinical features. A total of 98 patients with familial amyloid polyneuropathy and 37 asymptomatic mutation carriers (TTR Val30Met mutation), aged between 17 and 84 years, who underwent sural nerve biopsy between 1981 and 2017 at Centro Hospitalar Universitário do Porto were studied. Thirty-one controls were included for comparison. The median age at nerve biopsy was 26.0 [interquartile range = 23.5–39.5] years for asymptomatic mutation carriers, 45.0 [35.0–60.0] years for patients with familial amyloid polyneuropathy and 44.0 [30.0–63.0] years for controls. The median duration between nerve biopsy and symptoms’ onset was 7.0 [3.3–11.8] years (range: 1–27 years) in the asymptomatic carriers. Most patients were in an earlier disease stage (93% with a polyneuropathy disability scale ≤2). Patients had loss of small and myelinated fibres compared with both asymptomatic carriers and controls (P < 0.001), whereas asymptomatic carriers showed loss of small myelinated fibres when compared with controls (P < 0.05). The loss of myelinated fibres increased with disease progression (P < 0.001), and patients in more advanced clinical stage showed more frequent amyloid deposition in the nerve (P = 0.001). There was a positive correlation between large myelinated fibre density and time to symptoms’ onset in the asymptomatic carriers that developed early-onset form of the disease (r = 0.52, P < 0.01). In addition, asymptomatic carriers with amyloid deposition already present in sural nerve biopsies developed symptoms earlier than those with no amyloid (P < 0.01). In conclusion, this study confirms that the loss of small fibre size is an initial event in familial amyloid polyneuropathy, already present in asymptomatic gene carriers, starting several years before the onset of symptoms. We show for the first time that large myelinated fibres’ loss and amyloid deposition are pathological features that correlate independently with short period to the onset of symptoms for asymptomatic carriers that developed early-onset form of the disease. These findings are therapeutically relevant, as it would allow for a better interpretation of the role of disease-modifying agents in transthyretin familial amyloid polyneuropathy.
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Affiliation(s)
- Armindo Fernandes
- Institute of Biomedical Sciences Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Teresa Coelho
- Unidade Corino de Andrade, Department of Neurosciences, Centro Hospitalar do Porto, 4099-001 Porto, Portugalu
| | - Aurora Rodrigues
- Neuropathology Unit, Department of Neurosciences, Centro Hospitalar Universitário do Porto, 4099-001 Porto, Portugal
| | - Helena Felgueiras
- Department of Neurology, Centro Hospitalar Vila Nova de Gaia-Espinho, 4434-502 Vila Nova de Gaia, Portugal
| | - Pedro Oliveira
- Institute of Biomedical Sciences Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal.,Epidemiological Research Unit (EPIUnit), Institute of Public Health, Universidade do Porto, 4050-091 Porto, Portugal
| | - António Guimarães
- Neuropathology Unit, Department of Neurosciences, Centro Hospitalar Universitário do Porto, 4099-001 Porto, Portugal
| | - Manuel Melo-Pires
- Institute of Biomedical Sciences Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal.,Unidade Corino de Andrade, Department of Neurosciences, Centro Hospitalar do Porto, 4099-001 Porto, Portugalu.,Neuropathology Unit, Department of Neurosciences, Centro Hospitalar Universitário do Porto, 4099-001 Porto, Portugal
| | - Ricardo Taipa
- Institute of Biomedical Sciences Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal.,Unidade Corino de Andrade, Department of Neurosciences, Centro Hospitalar do Porto, 4099-001 Porto, Portugalu.,Neuropathology Unit, Department of Neurosciences, Centro Hospitalar Universitário do Porto, 4099-001 Porto, Portugal
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A New Method for Automated Identification and Morphometry of Myelinated Fibers Through Light Microscopy Image Analysis. J Digit Imaging 2017; 29:63-72. [PMID: 25986589 DOI: 10.1007/s10278-015-9804-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Nerve morphometry is known to produce relevant information for the evaluation of several phenomena, such as nerve repair, regeneration, implant, transplant, aging, and different human neuropathies. Manual morphometry is laborious, tedious, time consuming, and subject to many sources of error. Therefore, in this paper, we propose a new method for the automated morphometry of myelinated fibers in cross-section light microscopy images. Images from the recurrent laryngeal nerve of adult rats and the vestibulocochlear nerve of adult guinea pigs were used herein. The proposed pipeline for fiber segmentation is based on the techniques of competitive clustering and concavity analysis. The evaluation of the proposed method for segmentation of images was done by comparing the automatic segmentation with the manual segmentation. To further evaluate the proposed method considering morphometric features extracted from the segmented images, the distributions of these features were tested for statistical significant difference. The method achieved a high overall sensitivity and very low false-positive rates per image. We detect no statistical difference between the distribution of the features extracted from the manual and the pipeline segmentations. The method presented a good overall performance, showing widespread potential in experimental and clinical settings allowing large-scale image analysis and, thus, leading to more reliable results.
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Sanada LS, Tavares MR, Sato KL, Ferreira RDS, Neubern MCM, Castania JA, Salgado HC, Fazan VPS. Association of chronic diabetes and hypertension in sural nerve morphometry: an experimental study. Diabetol Metab Syndr 2015; 7:9. [PMID: 25717348 PMCID: PMC4339238 DOI: 10.1186/s13098-015-0005-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/02/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Prospective studies have shown incidence rates of hypertension in diabetes mellitus to be three times that of subjects without diabetes mellitus. The reverse also applies, with the incidence of diabetes two to three times higher in patients with hypertension. Despite this common clinical association, the contribution of each isolated entity in the development of a neuropathy is still not well understood. The aims of the present study were to investigate the presence of peripheral neuropathy in spontaneously hypertensive rats (SHR) and SHR with chronically induced diabetes, using a morphological and morphometric study of the sural nerves. METHODS Female SHR and normotensive Wistar rats (WR), 8 weeks old, received a single intravenous injection of streptozotocin (STZ) through the tail vein. Controls from both strains received vehicle. Twelve weeks after the injection, sural nerves were dissected and prepared for light microscopy. Morphometry of sural nerve fascicles and myelinated fibers was performed with the aid of computer software. RESULTS The sural nerve myelinated fibers were highly affected by experimental diabetes in normotensive rats, causing mainly the reduction of the fiber size. Hypertensive rats showed characteristics of small fiber neuropathy and a severe reduction of the number and density or Schwann cells. The association between diabetes and hypertension caused an increase on the average size of the myelinated fibers, pointing to a small fiber loss, associated to axonal atrophy. CONCLUSIONS Our study gives morphological support to the existence of a neuropathy due to hypertension, which is among one of the most common risk factors for diabetic neuropathy. The association between the two neuropathies showed to be a complex alteration, involving and including both, large and small fibers neuropathy. Hypertension caused, indeed, an exacerbation of the alterations already observed in experimental models of diabetic neuropathy.
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Affiliation(s)
- Luciana Sayuri Sanada
- />Department of Neuroscience and Behavioral Neurosciences, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP Brazil
| | | | - Karina Laurenti Sato
- />Departament of Physical Therapy, Federal University of Sergipe, Aracaju, SE Brazil
| | - Renata da Silva Ferreira
- />Department of Neuroscience and Behavioral Neurosciences, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Milena Cardoso Maia Neubern
- />Department of Neuroscience and Behavioral Neurosciences, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Jaci Ayrton Castania
- />Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Helio Cesar Salgado
- />Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Valéria Paula Sassoli Fazan
- />Department of Neuroscience and Behavioral Neurosciences, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP Brazil
- />Department of Surgery and Anatomy, School of Medicine of Ribeirão Preto, USP, Av. Bandeirantes 3900, Ribeirão Preto, SP Brazil
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Mekaj AY, Morina AA, Bytyqi CI, Mekaj YH, Duci SB. Application of topical pharmacological agents at the site of peripheral nerve injury and methods used for evaluating the success of the regenerative process. J Orthop Surg Res 2014; 9:94. [PMID: 25303779 PMCID: PMC4198735 DOI: 10.1186/s13018-014-0094-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 09/29/2014] [Indexed: 12/17/2022] Open
Abstract
Traumatic injuries of the peripheral nerves are very common. Surgical repair of the damaged nerve is often complicated by scar tissue formation around the damaged nerve itself. The main objective of this study is to present the recent data from animal experimental studies where pharmacological topical agents are used at the site of peripheral nerve repair. Some of the most commonly topical agents used are tacrolimus (FK506), hyaluronic acid and its derivatives, and melatonin, whereas methylprednisolone and vitamin B12 have been used less. These studies have shown that the abovementioned substances have neuroprotective and neuroregenerative properties though different mechanisms. The successes of the regenerative process of the nerve repair in experimental research, using topical agents, can be evaluated using variety of methods such as morphological, electrophysiologic, and functional evaluation. However, most authors agree that despite good microsurgical repair and topical application of these substances, full regeneration and functional recovery of the nerve injured are almost never achieved.
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Affiliation(s)
| | | | | | - Ymer H Mekaj
- Institute of Pathophysiology, Faculty of Medicine, University of Prishtina, Rrethi i spitalit p,n,, Prishtina 10000, Kosovo.
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